public string Subscribe(string uid, string topicFilter, Action <MqttApplicationMessageReceivedEventArgs> callback)
{
if (topicFilter == null)
{
throw new ArgumentNullException(nameof(topicFilter));
}
if (callback == null)
{
throw new ArgumentNullException(nameof(callback));
}
if (string.IsNullOrEmpty(uid))
{
uid = Guid.NewGuid().ToString("D");
}
lock (_subscribers)
{
_subscribers[uid] = new MqttSubscriber(uid, topicFilter, callback);
}
// Enqueue all retained messages to match the expected MQTT behavior.
// Here we have no client per subscription. So we need to adopt some
// features here manually.
var retainedMessages = _mqttServer.GetRetainedApplicationMessagesAsync().GetAwaiter().GetResult();
foreach (var retainedMessage in retainedMessages)
{
_incomingMessages.Add(new MqttApplicationMessageReceivedEventArgs(null, retainedMessage));
}
return(uid);
}
void TryNotifySubscriber(MqttSubscriber subscriber, MqttApplicationMessageReceivedEventArgs message)
{
try
{
subscriber.Notify(message);
}
catch (OperationCanceledException)
{
}
catch (Exception exception)
{
_logger.Log(LogLevel.Error, exception, $"Error while notifying subscriber '{subscriber.Uid}'.");
}
}
public string Subscribe(string uid, string topicFilter, Action <MqttApplicationMessageReceivedEventArgs> callback)
{
if (topicFilter == null)
{
throw new ArgumentNullException(nameof(topicFilter));
}
if (callback == null)
{
throw new ArgumentNullException(nameof(callback));
}
if (string.IsNullOrEmpty(uid))
{
uid = Guid.NewGuid().ToString("D");
}
lock (_subscribers)
{
_subscribers[uid] = new MqttSubscriber(uid, topicFilter, callback);
}
return(uid);
}